Production of colored photographic images by color development



Patented Nov.'12, 1940 I,

rnonuc'rlou or cononsn rn'o'rocnarn- 10 moms BY conon DEVELOPMENT JohnDavid Kendalland Ronald Bernard Collins,

Ilford, England,

assignors to Ilford Limit, 11-

ford, Essex, England, a. British company No Drawing, Application April 4, 1939, Serial no.

265,999. In Great 10 Claims.

The invention relates to the production of a colored photographic images by color develop- ,ment.

It is known that a colored image may be formed 5 simultaneously with the silver image obtained by developing an exposed silver halide. emulsion if a substance known as a "color former is employed, for example, if the color former is mixed with-the developer or incorporated in the emulll) sion. The colored image may be revealed by bleaching out the silver image with, for example, Farmers reducer or another known photographic bleaching agent.

It is an object of t s invention to provide a is new range of color formers. A further object of the invention is to provide a method of producing colored photographic images with the aid of such color formers and a still further object is to provide light sensitive silver halide photogo graphic materials containing the new color formers.

Other objects of the invention will appear hereinafter.

According to the invention a process for the 5 production or colored photographic images comprises developing a reducible silver salt image with an aromatic amino compound as the developer in the presence of a color former which is a 2-acyl1-l-naphthol in which .the 2 substituent consists of a carboxylic acyl group and in which the total substituents on the naphthalene nucleus contain between them at least three carbon atoms. The i-position in the naphthalene nucleus may be unsubstituted or may be substituted by a halogen atom.

The acyl group may be represented by the formula R-C0-, and R in this formula may be any hydrocarbon or substituted hydrocarbon radlcle. Thus B may be an alkyl group (preferably containing up to six carbon atoms) a substituted alkyl group, an-aryl group, e. g. a phenyl or naphthyl group, a substituted aryl group, an" aralkyl group, a g. a benzyl group, ora substituted aralkyl group. Substituents in the alkyl, aryl, or aralkyl group may be, for example, chlorine or bromine atoms or nitro,hydrox y, alkoxy, amino and substituted amino groups, the substituted alkyl, aryl, or aralkyl groups being preferably linked by one of their carbon atoms to the caro rl roup. 1

The new color formers, therefore, are compounds ,of the following general formula:

group, an aralkyl group or substituent groups in the Britain April 4, 1938 I in which R represents an alkyl group, preferably containing up to six carbon atoms, a substituted alkyl group, an aryl group, a substituted .aryl

a substituted aralkyl group linked by a carbon atom to the carbonyl group, Z represents a hydrogen atom or a halogen atom and the various X's, which may be the same 'or different, represent hydrogen atoms, halogen atoms or any monovalent substituent groups, e. g.

alkyl, aryl, aralkyl, amino, substituted amino, hy-

droxy, alkoxy, nitro, sulphonic ,acid or acyl groups, the group C0--R and one of the X's contaming .between them ,at least three carbon atoms. k

The compound 2 acetyl 1 naphthol, which since it does not contain 3 carbon atoms in substituent groups is not included in the present invention, is ,also capable of actin as a color former. However, this compound is very sensitive to the presence of sulphites such as are com monly included in developers to inhibit aerial oxidation. The color formers included in the present invention have, in general, a satisfactory, resistance to the action of ,sulphites and may be employed in conjunction with developers contaming sulphites. v

The developers used for developing colored photographic images with the aid of the color formers of the present invention do not, of course, necessarilyv contain sulphlte, and where the risk of oxidation of the developenis not a material factor, sulph-ites may be omitted;

As indicated above, awide range of 2-acyl-1- naphthols is included in the present invention. Thus, for example, simple 2-acyl-l-naphthols which contain no other substituent (i. e. where Z and all the Xs ofvthe above formula are hydrogen atoms and R contains at least two carbon atoms) are very suitable; examples are 2-acyl-1-naph thnls in which the acyl groups are the following: n-propionyl, n-butyryl, iso-butyryl, n-valeryl, isovaleryl, trimethylacetyl, caproyl, and heli yl, oenanthoyl, pelarg'onyl, lauryl, myristyl, palmityl, stearyl, benzoyl, phenylacetyl, phenylpropionyl and cinnamoyl. Again, the 2-acyl-l-naphthols may contain positions of X and Z in the above general formula. Thus, a very satisfactory color-former of the type where Z is an halogen atom is 2-propionyl-4-brom-l-naphol. 1 i

Again, the color formers may be of the time wherein one or more of the X's in the above for mula are monovalent substituent groups, e; g.- zzfi-di-acetyl 1 zfi-dihydroxy naphthalene and 2:6- di-n-butyryl 1:5-dihydroxynaphthalene.

Also included in the present invention are aoylnaphthols in which two naphthol residues are 'link edbytheresidueofadlbasicacidsuohasgo sucoinic acid or adipic acid.- An example oi type is 2:2'-succinoyl-1:1'-dinaphthol.

Suitable aromatic amino compounds which g may be employed as the developers in conjunction with the color-formers or this invention are H derivatives oip-phenylene-diamine and particularly the asymmetric dialkyl p-phenylenedi- V amines, e. g. p-aminodimethylaniline, p-aminodiethylaniline and p-aminodihutylaniline. Other developing agents which may 'be used include p-phenylenediamine itseli', p-methylaminoaniline, p-ethylaminoaniline and p-aminophenol," N.N diethyl o-phenylenediami-ne, phenylenediamine, 1,2,5 toluylenediamine,

noto'luene, and its dihydrochloride and a-y-dldiamine. These aromatic amino-developing agents may beused hydroxypropyl pphenylene in the form or their salts, which may be either inorganic or organic. The salts are in general more stable than the tree bases.

of the hydrochlorides, sulfates and acetates.

' The color formers may bemixed with the degraphic emulsions:

veloper, or incorporated in the emulsion. A specific example of a suitable developing solution is as follows: Dsvmormo SoLunon-A niethyl-p phenylene die hydrochloarm 1 Sodium carbonate crystals,

- NazCOaIOI-IsO gms Sodium sulphite crystals, NazSOs'lHsO" a 125, Color former (1% or a saturated'solution at room temperature in alcohol, whichever is the weaker) cc s 100 Distilled water to make litre 1 If desired, the sodium sulphite may be omitted,

A 25 its function being to fortify the solution against developers containing these compounds give dye.

images in varying shades of blue and blue-green and these dye images remain inthe gelatin layer after removal of the silver image by treatment with, for example, ers reducer.

In. tests carried'out with such developing solutions the time of development was two minutes at 65 F. but in many cases there were indica tions to show that this time was more than sumcient to produce the dye image required.

The following specific examples illustrate the use of the color formers as additions to seamize 2 Fifty cos. of a melted photographic emulsion containing essentially silver bromide in the proportion ofio gms. oi silver halide per kilogram were mixed with e. previously prepared mixture of 25 cos. of'a 10% gelatin solution and 25 cos. of-

al%' ethyl alcohol solution of 2-pmpionyl lnaphthol, and the emulsion was coated on paper in'the usual way. Test pieces of this coated paper were then exposed under a standard test negative and then developed for two minutes at 65 F. in .the'above developing solution-A but.

using equivalent ethyl alcohol in place of the color former solution, when a lame-green dyechloro pexamples of suitable salts mention is made mospheric pressure.

photoi image was iormedin association with the silver Example 2 Fifty cos. of a melted photographic emulsion containing essentially silver chloride in the proportion of gms. of silver halide per kilogram of emulsion were mixed with a previously prepared mixture of cos. of a 10% gelatin solution and 20 cos. of a 1% ethyl alcohol solution oi 2-iso-butyryl-1-naphthol. This emulsion was then coated upon paper and test pieces of the coated paper were exposed under a test negative and developed for 2 minutes at 65 F. in developing solution-A but using equivalent ethyl alcohol in place of .thepcolur-iormer solution.

A deep blue-green dye-image was produced in association with the silver image and the dyeimage remained in the gelatin layer after removal of the silver image by treatment with Farmers reducer. I

- Instead of the specific color-formers named in V the 2-position with an organic acid or organic acid anhydride in the presence of zinc chloride at a temperature between 160 and 200 C. at at-;

When a polybasic acid is employed it is possible that the product will consist wholly or partly of-a compound in which there is more than one naphthol nucleus. The use of such products is included within the process of the present invention.

v The process of development employing the color-formers in accordance with the present invention maybe applied either toga latent image in an emulsion of a silver halide which has been exposed 'to' the action of light, for example, in, a camera or behind a photographic negative image} or it may be applied to the residual unaltered silver halide left when an initial reduced silver image has been dissolved away as in the reversal process of development; or it may be applied to a developed photographic image in metallic silver which has been fixed by the removal of unaltered silver halide by means of solvents and subsequently converted to a developable silver salt by means of known photographic bleaching agents. In the'last two'cases, the residual silver halide and the silver salt respectivelyma'y be made developable by the action of light or in any other way, 9. g. by treatment with sodium arsenite.

We claim:

. 1. The method which comprises developing a photographic element containing a reducible silver salt image with an aromatic amino developing compound in the presence of an acyl naphthol comprising twonaphthol radicals linked by the diacyl radical of an aliphatic dibasic carhoxylic acid. r

2,22o ,ooa v 3 I I 8. A method as set iorth'in claim2 wherein the acyl naphthol is 2:2'-adipoyl-1:l'-dinaphthe acyl naphthol is 2:2'-succinoyl-1:l'-dinaphthol.

thol I 8. A photographic developer solution compris- 4. A' method as set forth in claim fl whe'rein ing an aromatic amino developing compound and i the acyl naphthol is 2:2'-adipcyl-1:1'-dinaphan acyl naphthol comprisins two naphthol radi- '5 thol. cals linked by the diacyl radicaloi an aliphatic 5. A light sensitive silver halide photographic dibasic carboxylic acid. v emulsion containins as a color iormer an acyl 9. A photographic developer solution comprisnaphthcl, comprising two naphthol radicals ing an aromatic amino developing compound and 0 linked by the diacyl radical of an aliphatic di- 2:2'-succinoyl-l1'-dinaphthol. 10

basic carboxylic acid. 10. A photographic developer solution com- ,6. An emulsion as set forth in claim 5 wherein prising an aromatic amino developing compound the acyl naphthol is 2:2'-succinoy1-1:1-dinaphand 2:2'-adipoyl-.l-l'-dlnaphthol. thOL' 1 JOHN DAVID KENDALL.

5 3!. An emulsion as set forth in claim 5 wherein nomm 3mm com. 6 

